The Model Railroad Luddite: Matchbox and Hot Wheels?

The question frequently comes up about using toy diecast vehicles such as Matchbox and Hot Wheels on an HO layout. You will hear "they are too big" for HO scale. Not necessarily true. Despite the stated scale of 1/64 (which happens to be S scale), Matchbox and Hot Wheels vehicles actually vary in scale.

Proof they are not too big. This Matchbox Scenicruiser bus measures the correct 40 feet long - in N scale!

Scenicruiser specifications - source

This is because of two criteria:

1. They have a MINIMUM size. Since they are classified as toys, they must follow regulations set by the CPSC (Consumer Products Safety Commission), which requires toys to pass the swallow test by not passing through a cylindrical opening of a certain size. (Actual HO vehicles marketed to modelers are clearly labelled NOT A TOY in order to be exempt from this requirement.)

2. They also have a MAXIMUM size, defined by their manufacturing tooling and blister packaging requirements.

So vehicles are scaled up or down as needed to fit within those parameters. Passenger cars, being the midrange of vehicle sizes, tend to be the advertised 1/64; yes, larger than HO scale. Stuff we can use for HO models would be larger-prototypes such as buses, trucks, or construction equipment; where deviations from scale are not noticeable to the eye. (Except to the eyes of the rivet counters who visit me occasionally!).

Here are some Matchbox/Hot Wheels vehicles in use on my HO layout. Some have had modifications. Many of them only need some dots of paint for lights and have a license plate painted in.